1. Field of the Invention
The present invention relates to a cartridge detachably mounted to image forming apparatuses, such as photocopiers and printers of forming images onto recording material by utilizing an electrophotographic system.
2. Related Background Art
In order to improve replaceability of parts, there is such an image forming apparatuses adopting an electrophotographic system that is provided with a cartridge detachably mounted to the image forming apparatus derived by unitizing a plurality of members. For example, there is such a cartridge that removes toner still remaining on a photosensitive member or a transfer belt due to failure in complete consumption for transfer from a photosensitive member or recording material onto a transfer belt to discharge it as waste toner.
In this case, the main body apparatus comprises a housing container of housing waste toner discharged from this cartridge and waste toner carrying means in order to retrieve (or recover) it to the housing container.
There exists a circulation unit of bringing mutual orifices into communication in order to deliver waste toner between this cartridge and the waste toner carrying means (or the housing container), and shutter means is provided so that the orifice of this delivery unit is opened and closed and the toner is not scattered to the outside. Thus, shutter means is essential for the cartridge system detachably mounted to the main body apparatus in order to prevent toner leakage from the cartridge at the time of cartridge replacement (see, for example, Japanese Utility Model Application Laid-Open No. H04-81172).
However, a waste toner shutter in a prior art cartridge in the attach/detach system has presented problems as described below. That is, when a cartridge is detached from/attached to the main body apparatus, a user might touch by mistake the waste toner shutter provided to the cartridge, and then the toner shutter would open to leak toner from the waste toner from a discharge port. In addition, such a problem was present that toner would be stuck (or attracted) onto the surface of the cartridge by the toner leaking from the waste toner receiving port provided in the main body side when the cartridge was mounted onto the main body of the image forming apparatus.